Examining how the Civil War death toll, which is estimated to have been 750,000 people (2.5 percent of the nation's population at the time), affected the nation's psyche. Based on Harvard president Drew Gilpin Faust's book "This Republic of Suffering," the documentary includes remarks from her and fellow historians David W. Blight, Vincent Brown, J. David Hacker and Mark S. Schantz; poet Thomas Lynch; Adm. Mike Mullen (USN Ret.), a former chairman of the Joint Chiefs of Staff; and George Will.